New Zealand Guidelines for cyanobacteria in recreational fresh waters: Interim Guidelines

This document is divided into four main sections, plus 14 appendices. Section 1. Introduction provides an overview of the purpose and status of the document as well as advice on who should use it. Section 2. Framework provides a background to the overall guidelines approach, recommendations on agency roles and responsibilities, and information on the condition of use of this document. Section 3. Guidelines describes the recommended three-tier monitoring and action sequence for planktonic and benthic cyanobacteria. Section 4. Sampling provides advice on sampling planktonic and benthic cyanobacteria. The appendices give further background information and include templates for data collection and reporting, including: • background information on known cyanotoxins and their distribution in New Zealand • information on the derivation of guideline values • photographs of typical bloom events • a list of biovolumes for common New Zealand cyanobacteria • templates for field assessments • suggested media releases and warning sign templates. A glossary provides definitions for abbreviations and terms used in these guidelines

Investigating the Interactions Between Cyanobacteria and Vibrio parahaemolyticus

One well-known pathogen that has been the topic of many recent studies is Vibrio parahaemolyticus, which causes thousands of foodborne illnesses a year, mostly from the ingestion of raw or undercooked oysters. It has been shown cyanobacteria can act as a long-term reservoir of Vibrio cholerae, another pathogenic Vibrio, by encasing the cells within mucilaginous sheaths during which Vibrios enter a viable but non-culturable state. In this study we investigated the interaction of V. parahaemolyticus with cyanobacteria to determine whether cyanobacteria aid in the longevity and survival of V. parahaemolyticus. We found that non-pathogenic V. parahaemolyticus strain G445 was able to persist better in the presence of cyanobacteria compared to pathogenic V. parahaemolyticus MDOH-04-5M732. G445 cells seem to cluster non-discriminately within the cyanobacterial mats, which may be due to specific interactions with cyanobacteria, yet further investigation is necessary

Dating the cyanobacterial ancestor of the chloroplast

Cyanobacteria have played a pivotal role in the history of life on Earth being the first organism to carry out oxygenic photosynthesis, which changed atmospheric chemistry and allowed the evolution of Eukarya. Chloroplasts are the cellular organelles of photoautotrophic eukaryotes in which photosynthesis is conducted. Although the initial suggestion from Mereschkowsky (1905) that cyanobacteria are the ancestors of chloroplasts was greeted with skepticism, the idea is now widely accepted. Here we attempt to resolve and date the cyanobacterial ancestry of the chloroplast using phylogenetic analysis and molecular clocks, because until now, the long-standing question of, from which, among the vast diversity of cyanobacteria, did chloroplasts evolve, has not been resolved. We found that chloroplasts form a monophyletic lineage, are most closely related to subsection I, N2-fixing unicellular cyanobacteria (Order Chroococcales), and heterocyst-forming Order Nostocales cyanobacteria are their sister group. The appearance of Nostocales and of Chroococcales occurred during the Paleoproterozoic, and chloroplasts appeared in the mid-Proterozoic. The capability of N2-fixation in cyanobacteria appeared once during the late Archaen and early Proterozoic eons. Furthermore, we found that oxygen-evolving cyanobacteria could have appeared in the Archean. Our results suggest that a free-living cyanobacterium with the capacity to store starch via oxygenic CO2 fixation, and to fix atmospheric N2, would be a very important intracellular acquisition, which, as can be recounted today from several lines of evidence, would have become the chloroplast by endosymbiosis

Physiological and Metabolic Responses of Marine Mussels Exposed to Toxic Cyanobacteria Microcystis aeruginosa and Chrysosporum ovalisporum

Toxic cyanobacterial blooms are a major contaminant in inland aquatic ecosystems. Furthermore, toxic blooms are carried downstream by rivers and waterways to estuarine and coastal ecosystems. Concerning marine and estuarine animal species, very little is known about how these species are affected by the exposure to freshwater cyanobacteria and cyanotoxins. So far, most of the knowledge has been gathered from freshwater bivalve molluscs. This work aimed to infer the sensitivity of the marine mussel Mytilus galloprovincialis to single as well as mixed toxic cyanobacterial cultures and the underlying molecular responses mediated by toxic cyanobacteria. For this purpose, a mussel exposure experiment was outlined with two toxic cyanobacteria species, Microcystis aeruginosa and Chrysosporum ovalisporum at 1 × 105 cells/mL, resembling a natural cyanobacteria bloom. The estimated amount of toxins produced by M. aeruginosa and C. ovalisporum were respectively 0.023 pg/cell of microcystin-LR (MC-LR) and 7.854 pg/cell of cylindrospermopsin (CYN). After 15 days of exposure to single and mixed cyanobacteria, a depuration phase followed, during which mussels were fed only non-toxic microalga Parachlorella kessleri. The results showed that the marine mussel is able to filter toxic cyanobacteria at a rate equal or higher than the non-toxic microalga P. kessleri. Filtration rates observed after 15 days of feeding toxic microalgae were 1773.04 mL/ind.h (for M. aeruginosa), 2151.83 mL/ind.h (for C. ovalisporum), 1673.29 mL/ind.h (for the mixture of the 2 cyanobacteria) and 2539.25 mL/ind.h (for the non-toxic P. kessleri). Filtering toxic microalgae in combination resulted in the accumulation of 14.17 ng/g dw MC-LR and 92.08 ng/g dw CYN. Other physiological and biochemical endpoints (dry weight, byssus production, total protein and glycogen) measured in this work did not change significantly in the groups exposed to toxic cyanobacteria with regard to control group, suggesting that mussels were not affected with the toxic microalgae. Nevertheless, proteomics revealed changes in metabolism of mussels related to diet, specially evident in those fed on combined cyanobacteria. Changes in metabolic pathways related with protein folding and stabilization, cytoskeleton structure, and gene transcription/translation were observed after exposure and feeding toxic cyanobacteria. These changes occur in vital metabolic processes and may contribute to protect mussels from toxic effects of the toxins MC-LR and CYNPortuguese Science Foundation and under the Projects MOREBIVALVES (PTDC/ASP-PES/31762/2017) and UID/Multi/04423/2013NORTE 2020, Portugal 2020 and the European Union through the ERDF, and by FCT. Moreover, Project AGL2015-64558-RMINECO/FEDER, UE, and the grant FPI (BES-2016–078773

Occurrence and Distribution of Cyanobacteria and their Toxins in Silver Lake, New Hampshire

A study of Silver Lake, NH was performed as part of a 5-lake assessment of cyanobacteria prevalence and distribution. Multi-parameter fluorescence probe measurements of chlorophyll a and cyanobacteria concentrations (PC, phycocyanin fluorescence) were evaluated in addition to physical and chemical characteristics of the lake. Silver Lake did not exhibit summer stratification suggesting a recent mixing event. It had oligotrophic levels of Chlorophyll a (1.93 ± 0.06 mg L-1) and of TP (10.10 mg L-1), yet PC levels were the highest of all the lakes studied (248691 ± 963 Microcystis cell equivalents mL-1). The cyanobacteria Microcystis dominated the phytoplankton community. Microcystin levels varied from a mean 72.43 ± 21.21 pg mL-1 in transect water to 137.69 ± 46.9 pg mL-1 in sediment water. Chlorophyll distribution was rather homogeneous while cyanobacteria levels were highest towards the shallow, embayed NE part of the lake where a section of a State Park beach is located. Implications include potential increase in exposure to toxins by water users. Heterogeneous distribution of cyanobacteria emphasizes the importance of extensive sampling beyond pelagic sampling sites to more accurately inform decision-making regarding health and safety of water bodies

An Integrative Remote Sensing Application of Stacked Autoencoder for Atmospheric Correction and Cyanobacteria Estimation Using Hyperspectral Imagery

Hyperspectral image sensing can be used to effectively detect the distribution of harmful cyanobacteria. To accomplish this, physical- and/or model-based simulations have been conducted to perform an atmospheric correction (AC) and an estimation of pigments, including phycocyanin (PC) and chlorophyll-a (Chl-a), in cyanobacteria. However, such simulations were undesirable in certain cases, due to the difficulty of representing dynamically changing aerosol and water vapor in the atmosphere and the optical complexity of inland water. Thus, this study was focused on the development of a deep neural network model for AC and cyanobacteria estimation, without considering the physical formulation. The stacked autoencoder (SAE) network was adopted for the feature extraction and dimensionality reduction of hyperspectral imagery. The artificial neural network (ANN) and support vector regression (SVR) were sequentially applied to achieve AC and estimate cyanobacteria concentrations (i.e., SAE-ANN and SAE-SVR). Further, the ANN and SVR models without SAE were compared with SAE-ANN and SAE-SVR models for the performance evaluations. In terms of AC performance, both SAE-ANN and SAE-SVR displayed reasonable accuracy with the Nash???Sutcliffe efficiency (NSE) > 0.7. For PC and Chl-a estimation, the SAE-ANN model showed the best performance, by yielding NSE values > 0.79 and > 0.77, respectively. SAE, with fine tuning operators, improved the accuracy of the original ANN and SVR estimations, in terms of both AC and cyanobacteria estimation. This is primarily attributed to the high-level feature extraction of SAE, which can represent the spatial features of cyanobacteria. Therefore, this study demonstrated that the deep neural network has a strong potential to realize an integrative remote sensing application

Cyanobacteria blooms cannot be controlled by effective microorganisms (EM) from mud- or Bokashi-balls

In controlled experiments, the ability of ‘‘Effective Microorganisms (EM, in the form of mudballs or Bokashi-balls)’’ was tested for clearing waters from cyanobacteria. We found suspensions of EM-mudballs up to 1 g l-1 to be ineffective in reducing cyanobacterial growth. In all controls and EM-mudball treatments up to 1 g l-1 the cyanobacterial chlorophyll-a (Chl-a) concentrations increased within 4 weeks from&120 to 325–435 lg l-1. When pieces of EM-mudballs (42.5 g) were added to 25-l lake water with cyanobacteria, no decrease of cyanobacteria as compared to untreated controls was observed. In contrast, after 4 weeks cyanobacterial Chl-a concentrations were significantly higher in EM-mudball treatments (52 lg l-1) than in controls (20 lg l-1). Only when suspensions with extremely high EM-mudball concentrations were applied (i.e., 5 and 10 g l-1), exceeding the recommended concentrations by orders of magnitude, cyanobacterial growth was inhibited and a bloom forming concentration was reduced strongly. In these high dosing treatments, the oxygen concentration dropped initially to very low levels of 1.8 g l-1. This was most probably through forcing strong light limitation on the cyanobacteria caused by the high amount of clay and subsequent high turbidity of the water. Hence, this study yields no support for the hypothesis that EM is effective in preventing cyanobacterial proliferation or in terminating blooms. We consider EM products to be ineffective because they neither permanently bind nor remove phosphorus from eutroficated systems, they have no inhibiting effect on cyanobacteria, and they could even be an extra source of nutrients

An ecological assessment of the trophic structure of York Pond in Coos County Milan, NH

We examined the physical, chemical and biological properties of York Pond in Coos County Milan, NH as a part of a 6-lake study. Chemical and physical characteristics measured included: total phosphorus and nitrogen, turbidity, light profiles with Secchi disk depth, specific conductivity, oxidation-reduction potential, dissolved oxygen, and temperature. Biological analysis included: phytoplankton percentage, chlorophyll a fluorescence, zooplankton abundance and zooplankton biomass. York Pond had eutrophic levels of several parameters in the epilimnion, including: chlorophyll a (39.4 + 1.04 µgL-1), total phosphorus (46.3 + 0.67 µgL-1), total nitrogen (843.3 + 18.48 µgL-1), turbidity (22.0 + 0.09 NTU), and percentage of cyanobacteria at (42.0 + 9.60 %). Cyanobacteria were even more dominant deeper in the water column, making up more than 70% of the net phytoplankton. The primary source of nutrient loading appears to be effluent from the fish raceways at the Berlin fish hatchery. Eutrophication has shifted the phytoplankton of York Pond toward cyanobacteria, with Anabaena as the dominant genus in the fall. The could have impacts across multiple trophic levels. Comparisons of York Pond to other study lakes suggest that Secchi disk, chlorophyll a and total phosphorus may be useful predictors of cyanobacteria dominance in New England lakes

Bioaccumulation of Microcystins by Freshwater Mussels in Mystic Lake and Middle Pond, MA

The UNH Center for Freshwater Biology investigated a possible relationship between a cyanobacteria bloom and a large-scale die-off of freshwater mussels in Mystic Lake and Middle Pond (Barnstable, MA). Four mussel species, Elliptio complanata (Eastern Elliptio), Pyganodon cataracta (Eastern Floater), Leptodea ochracea (Tidewater Mucket), and Lampsilis radiata (Eastern Lampmussel) (Nedeau, 2008), along with water samples, were collected from these lakes on August 9, 2010 (during bloom) and again on September 29 and October 8, 2010 (post-bloom). Hepatopancreas tissue, foot tissue, and water samples were tested for the cyanobacteria toxins, microcystins (MC), using ELISA techniques. MC concentrations in the hepatopancreas were generally higher (171.2 ng MC g-1 dry weight (dw)) than in the muscle (foot) tissue (55.8 ng MC g -1 dw) for each species. Average microcystin concentrations in mussels sampled during postbloom tissues were slightly lower (161.6 ng MC g-1 dw) than those collected during the cyanobacteria bloom (171.2 ng MC g1 dw). Live mussels were also subjected to a depuration experiment to determine the release of MC from mussels into the water. Mussels that were placed in cyanobacteria-free water depurated 61-90% MC within the first few days demonstrating their ability to release free MC-cyanotoxins into the lake water